Separation of the constituents of complex sulfid ores.



Unrrnn dramas PATENT rerun.

MAX MATTHIAS HAFF, OF NEW YORK, N. Y., ASSIGNOR TO THE AMPEREELECTROCHEMICAL COMPANY, OF JERSEY CITY, NElY JERSEY, A COR- PORATION OFNEXV JERSEY.

SEPARATION OF THE CONSTITUENTS OF COMPLEX SULFID ORES.

SPECIFECATION forming part of Letters Patent No. 695,306, dated March 11, 1902.

Application filed June 29, 1901. Serial No. 66,589. (No specimens.)

T (ZZZ whom it may concern.-

Be it known that I, MAX MATTIIIAS I-IAFF, a subject of the King of GreatBritain and Ireland, residing at New York, in the county and 5 State ofNew York, have invented certain new and useful Improvements in theSeparation of the Constituents of Complex Sulfid Ores, of which thefollowing is a specification.

This invention relates to the utilization of IO complex ores consistingof mixed sulfids of zinc lead,and other metals,which do not yieldreadily to the usual metallurgical methods so as to enable a full andcomplete separation of the constituent metals. By fusion and roast- ;5ing with alkali-metal sulfates these complex sulfids may be convertedinto sulfates, with exception of the iron, which passes into ferricoxid, and by lixiviation the zinc sulfate may then be separated from thelead sulfate.

The resulting solution of zinc sulfate and sodiu m sulfate is, however,not salable as such, and the separation of these bases, whiletheoretically practicable, is not commercially practicable by ordinarymeans, as any of the 2 5 usual precipitates for the ZlHC will give a newmixed solution involving just so much waste. To overcome thisdifficulty, it is desirable to precipitate the zinc by an agent, whichwill itself be precipitated at the same time, so as 0 to leave thesodium sulfate alone in solution, thus enabling the recovery andreutilization of the latter. Such an agent is found in barium hydrate,which when added in proper proportion to the mixed solution causes a 5complete precipitation of both the zinc and the barium as zinc hydrateand barium sulfate, respectively. As an agent for the conversion of thesulfid into sulfate I prefer to use acid sodium sulfate; but the normalsul- 4o fate can also be used,with, however, an inferior result. Theacid or normal sulfate of any of the other fixed alkalies may also beused. In case the normal sulfate is used the conversion is aided by thetendency of the sul- 5 fate to break up under these conditions.

The process is carried out as follows: Two parts of the finely-groundore containing the mixed sulfids are mixed with six to seven parts ofacid sodium sulfate or generally of acid sulfate of a fixed alkali. Themixture is then heated in a suitable roasting-furnace to such atemperature as will cause the iron sulfate formed to be decomposed, thereactions in this operation being as follows:

If iron snlfid is present, it will be converted into ferric oxid, asfollows:

The mass is taken from the furnace and placed in a lixiviating-vat,wherein it is leached with water, thus extracting all the zinc sulfateand sodium sulfate,which enter into solution,leaving the lead sulfateand the ferric oxid in the residuum, from which they may be recovered bythe usual metallurgical processes. The mixed solution of zinc sulfateand sodium sulfate is drawn off and treated with sufficient bariumhydrate to just precipitate all of the zinc present according to thefollowing reaction:

ZnSO,+Bal-I O :ZnH O +BaSO This precipitate is separated fromthesolution of sodium sulfate by decanting or filtering and washing andforms a product which is useful as a pigment and salable as such. Thenormal sodium sulfate remaining in the solution may then be treated withsulfuric acid to convert it into acid sodium sulfate. The sulfuric acidrequired for this purpose may be derived from the roasting operationabove described. In fact, the sodium salt may be considered only as acarrier for the sulfuric o acid the latter being derived eventually fromthe ore itself, so that a given quantity of sodium sulfate can convertan indefinite quantity of the ore.

If gold and silver be present in the ore, the gold will pass along withthe iron and lead and may be recovered from thelead after reduction,while the silver will pass with the zinc and may be precipitated by zincehlorid previous to precipitation of the zinc. The I00 amount of zincohlorid so added would not in general be enough to enter seriously intothe subsequent reactions.

Having thus described my invention, the following is what I claim as newtherein and desire to secure by Letters Patent:

1. The process which consists in heating mixed sulfids of zinc and leadwith sulfate of an alkali metal, treating the resultant mass with adissolving agent to dissolve the zinc sulfate and alkali-metal sulfate,While leaving the lead sulfate undissolved and adding barium hydratetothe mixed solution of zinc sulfate and alkali-metal sulfate toprecipitate zinc hydrate and barium sulfate.

2. The process which consists in heating mixed sulfids of zinc and leadwith acid sulfate of an alkali metal, treating the resultant mass withwater to dissolve the sulfates of zinc and alkali metal, and addingbarium hydrate to the resulting solution to precipitate zinc hydrateandbarium sulfate, leaving the alkali-metal sulfate in solution.

3. The process which consists in heating mixed sufids of zinc and leadwith acid sulfate of an alkali metal, treating the resultant mass withwater to dissolve the sulfates of zinc and alkali metal, adding bariumhydrate to the resulting solution to precipitate zinc hydrate and bariumsulfate, leaving the alkali-metal sulfate in solution, recovering thealkali-metal sulfate, treating it with sulfuric acid to convert it intoacid sulfate and utiliz ing the latter in a repetition of the process.

4. The process which consists in roasting mixed sulfids of zinc and leadwith acid sulfate of an alkali metal, thereby producing sulfates of leadand zinc and sulfur dioxid, producing sulfuric acid from the latter byusual means, treating the sulfates of zinc, lead and alkali metal withwater to dissolve the sulfates of zinc and alkali metal, adding bariumhydrate to the solution to precipitate zinc hydrate and barium sulfate,recovering the alkali-metalsulfate from the solution, and treating itwith the sulfuric acid produced from the roasting process to obtain acidsulfate of the alkali metal for utilization in repetition of theprocess.

MAX MATTHIAS HAFF.

Witnesses:

J. GREEN, A. P. KNIGHT,

